Backstory: I know little to nothing about networking, but I hate paying rental fees, so I've always bought my own modem/ router. I had been using a tp link cr700 with 400mbps service from Astound. If I stood next to the router I could get >=400 on my phone, but the signal degraded significantly around my house (1800 sf, two floors). I would notice this the most streaming video on the second floor where the speed was about 100. Lots of buffering and pixelation, not always but frequently. Since the cr700 is pretty old I thought I would upgrade.
Issue: I got a motorola mb7621 and a tp link ax55. I don't notice any issues with performance, and I haven't had it long but it seems qualitatively that there's an improvement. Streaming works fine from any device, and I can stream from multiple devices at the same time. But when I run a speed test (ookla or ubiquiti) standing right next to the router I get ~7mbps down and <1 up (ookla) or >=7 (ubiquiti). What's going on?
The streaming is the best speed test of all... there may be a speedtest site that works best with your provider that you may have missed or the AI just sent you to the wrong one.
Also, do you use a wireless mesh or extender for your home? Best results tend to go with mesh systems.